At&t Bell Laboratories

Bell Telephone Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

Samuel L McCall, Jr

Jack L Jewell

Thirumalai N Venkatesan

Hyatt McDonald Gibbs

Richart Elliott Slusher

Kuochou Tai

Greg E Blonder

Edwin Arthur Chandross

Bernard Yurke

Kenneth William West

Anthony F Levi

Philip Moss Platzman

Kai-Feng Huang

Seng-Tiong Ho

Louis D Lanzerotti

Lasing threshold for a whispering mode laser is reduced by appropriate placement of a reflector. A reflector parallel to, and within a wavelength distance of, the disk decreases radiation loss due to imperfect internal reflection. Enhancement is calculable on the basis of destructive interference between reflected and direct radiation.

Integrated optics

Device for electromagnetic emission depends on total internal reflection-on whispering gallery mode cavitation about the periphery of a disk-shaped element of sub-wavelength thickness. As a laser, operating above threshold, the design is alternative to that of the Surface Emitting Laser for integration in integrated circuitry-either all-optic or electro-optic. Operating below threshold, it may serve as a Light Emitting Diode. The same operational considerations-based on improved efficacy for whispering gallery mode devices as due to relevant dimension/s of sub-wavelength thickness-is of consequence for a category of devices serving other than as simple emitters. Such three port devices may serve as switches, modulators, etc.

Whispering mode micro-resonator

Distributed Bragg Reflectors of high efficacy based on alternating layers of large difference in refractive index are fabricated by epitaxial growth followed by etchant removal and back-filling to produce a structure in which alternation is between layers of retained epitaxially grown material and layers of back-filled material. Such reflectors may serve simply as mirrors or may be incorporated in a variety of devices including lasers, LEDs, detectors, optical switches in which the DBRs serve e.g. for cavitation.

Distributed Bragg reflectors and devices incorporating same

Optical integrated circuitry, performing various of the functions associated with electronic integrated circuitry, is disclosed. Fabrication, importantly to achieve high circuit chip density--typically in the range of 10.sup.6 as including both devices and interconnecting guides--is dependent upon device/spacing dimension miniaturization resulting from fabrication in very thin layers. Typical layer thickness as retained in fabricated devices and guides, of a maximum of the order of a 1/2 wavelength for relevant photon flux, results in limitation in cross-talk to permit device design rules of one or a few wavelengths.

Optical integrated circuit designed to operate by use of photons

A semiconductor multiple quantum well mesa structure, for use as the optically active element in an optical logic or an optically controlled optical switching device, has its side surfaces implanted with surface recombination centers, whereby the optical switching speed is increased.

Semiconductor mesa structured optical processing devices, with added

Distributed feedback mirror cavities are found capable of sufficient reflectance-loss characteristics to permit lasing in two or a single quantum well structure in which lasing is in the thin (quantum) dimension. Such lasers sometimes known as 'quantum well surface emitting lasers' are of sufficiently low threshold value as to permit use in integrated circuits of high integration density--e.g. at 1 micron design rules. Anticipated uses, now made possible, include optical circuitry for computer chip interconnect as well as optoelectric integrated circuits for many purposes including computing itself.

Quantum well vertical cavity laser

Apparatus according to the invention comprises an optical, or opto-electronic device that comprises one or more 'trapping' layers that can speed the decay of a non-equilibrium carrier distribution in an active region of the device, thereby improving device characterstics. In preferred embodiments the trapping layers are arranged so as to increase the likelihood of radiative recombination of carriers leading to erased heat sinking requirements.

Optical or opto-electronic device having a trapping layer in contact

The inventive method for forming monolithic nonlinear Fabry-Perot etalons comprises depositing on an appropriate substrate, e.g., a GaAs wafer, a first multilayer mirror, depositing on the first mirror a spacer typically comprising optically nonlinear material, and depositing a second multilayer mirror onto the spacer. Typically, at least one of the mirrors is an active mirror comprising optically nonlinear material. Deposition can be by a known process, e.g., by MBE or MOCVD. Since, inter alia, the method comprises no critical etching steps it can be used to produce high finesse etalons that have uniform properties over relatively large areas. The inventive method can be adapted to the manufacture of transmissive etalons. It can also be used to produce arrays of optically isolated etalons. Devices comprising nonlinear etalons manufactured by the inventive method can be incorporated, for instance, into optical data processing apparatus, or into optical communications apparatus.

Apparatus comprising a monolithic nonlinear Fabry-Perot etalon, and

A distributed-feedback laser includes in its grating a localized phase-slip discontinuity which is placed off-center. Such discontinuity results in a quarter-wave phase slip, and it can be placed, e.g., such as to maximize the difference between threshold gain of the lowest-lasing mode and cavity loss of the next-to-lowest-lasing mode. The invention is applicable especially where laser output intensity differs at two output facets and results in enhanced mode selectivity during laser operation.

Distributed-feedback laser having enhanced mode selectivity

A new mode of operation of an optical cavity is disclosed. In this 'regenerative pulsation' mode, a substantially nonvarying input yields an output consisting of a train of pulses. Fractional modulations exceeding 90 percent are demonstrated.

Instability and regenerative pulsation in optical cavities

A device is disclosed which is capable of amplifying optical signals. The absorptive and dispersive properties of a cavity-enclosed nonlinear medium are combined with the transmission properties of the cavity to yield an input-output characteristic curve that displays gain or bistability.

Growing community of inventors

Chatham, NJ, United States of America

Samuel L McCall, Jr